Multiphoton ionization as a clock to reveal molecular dynamics with intense short x-ray free electron laser pulses.

We investigate molecular dynamics of multiple ionization in N2 through multiple core-level photoabsorption and subsequent Auger decay processes induced by intense, short x-ray free electron laser pulses. The timing dynamics of the photoabsorption and dissociation processes is mapped onto the kinetic energy of the fragments. Measurements of the latter allow us to map out the average internuclear separation for every molecular photoionization sequence step and obtain the average time interval between the photoabsorption events. Using multiphoton ionization as a tool of the multiple-pulse pump-probe scheme, we demonstrate the modification of the ionization dynamics as we vary the x-ray laser pulse duration.

Ultraintense x-ray induced ionization, dissociation, and frustrated absorption in molecular nitrogen.

Sequential multiple photoionization of the prototypical molecule N2 is studied with femtosecond time resolution using the Linac Coherent Light Source (LCLS). A detailed picture of intense x-ray induced ionization and dissociation dynamics is revealed, including a molecular mechanism of frustrated absorption that suppresses the formation of high charge states at short pulse durations. The inverse scaling of the average target charge state with x-ray peak brightness has possible implications for single-pulse imaging applications.

Auger electron angular distribution of double core-hole states in the molecular reference frame.

The Linac Coherent Light Source free electron laser is a source of high brightness x rays, 2×10(11) photons in a ∼5 fs pulse, that can be focused to produce double core vacancies through rapid sequential ionization. This enables double core vacancy Auger electron spectroscopy, an entirely new way to study femtosecond chemical dynamics with Auger electrons that probe the local valence structure of molecules near a specific atomic core. Using 1.1 keV photons for sequential x-ray ionization of impulsively aligned molecular nitrogen, we observed a rich single-site double core vacancy Auger electron spectrum near 413 eV, in good agreement with ab initio calculations, and we measured the corresponding Auger electron angle dependence in the molecular frame.

Double core-hole production in N2: beating the Auger clock.

We investigate the creation of double K-shell holes in N2 molecules via sequential absorption of two photons on a time scale shorter than the core-hole lifetime by using intense x-ray pulses from the Linac Coherent Light Source free electron laser. The production and decay of these states is characterized by photoelectron spectroscopy and Auger electron spectroscopy. In molecules, two types of double core holes are expected, the first with two core holes on the same N atom, and the second with one core hole on each N atom. We report the first direct observations of the former type of core hole in a molecule, in good agreement with theory, and provide an experimental upper bound for the relative contribution of the latter type.

Phase measurement of resonant two-photon ionization in helium.

We study resonant two-color two-photon ionization of helium via the 1s3p (1)P(1) state. The first color is the 15th harmonic of a tunable Ti:sapphire laser, while the second color is the fundamental laser radiation. Our method uses phase-locked high-order harmonics to determine the phase of the two-photon process by interferometry. The measurement of the two-photon ionization phase variation as a function of detuning from the resonance and intensity of the dressing field allows us to determine the intensity dependence of the transition energy.

Do cancer patients with chemotherapy-induced leukopenia benefit from an antiseptic chlorhexidine-based oral rinse? A double-blind, block-randomized, controlled study.

Patients undergoing cancer chemotherapy frequently suffer from mucositis, particularly if they become leukopenic (leucocytes <1000/microL). To identify a possible benefit from antiseptic rinsing of the oral cavity, 47 patients were randomized to rinse either with a chlorhexidine-based product (chlorhexidine concentration 0.3%; N=24) or with an amine-stannous fluoride combination (control group; N=23). Patients were asked to rinse three times a day for 30s from the beginning of chemotherapy until the end of leukopenia. Before rinsing, as well as during and after leukopenia, aerobic and anaerobic bacteria in the oral cavity were counted. At the same time, the patients were assessed for mucositis. In the chlorhexidine-based group, a significant decrease of the aerobic (P=0.042) and anaerobic (P=0.008) bacterial flora was identified. In the control group, the numbers of aerobic and anaerobic bacteria remained unchanged (P>0.05). Fifteen patients in the chlorhexidine-based group had a C-reactive protein (CRP) increase >50mg/L, compared with only eight patients in the control group [odds ratio: 3.13, confidence interval (CI) 0.82-12.39]. Nine patients in the chlorhexidine-based group but only two patients in the control group developed severe mucositis. This difference was statistically significant with an odds ratio of 6.30 (CI: 1.02-49.67). As not all of the 47 patients developed severe leukopenia, a separate analysis was carried out for patients with <1000 leucocytes/microL for a minimum of three days. The results of the microbial counts were very similar, with a clear reduction in the chlorhexidine group and no major alterations in the control group. Twelve of 15 patients in the chlorhexidine-based group had a CRP >50mg/L whereas only eight of 15 patients did so in the control group, which can be regarded as a slightly elevated risk for a CRP increase in the former group. Seven of 15 patients developed severe mucositis in the chlorhexidine-based group, but only two of 15 patients in the control group. These differences were not significant, but patients treated with chlorhexidine-based product seemed to have more problems with inflammation of the oral mucous membranes, resulting in an elevated mucositis score and a CRP increase. Other parameters such as body temperature or application of antibiotics did not differ between the two groups. We conclude that treatment with the chlorhexidine-based product did not provide a clinical benefit for cancer chemotherapy patients. On the contrary, the risk of mucositis and clinical sequelae seems to be enhanced, although the counts of micro-organisms on the oral mucous membranes are significantly reduced.

Right hemisphere dysfunction: therapeutic intervention from acute care to home health.

This article discusses clinical practice variances in speech-language treatment of patients with right hemisphere dysfunction by therapeutic milieu. With an eye toward enhanced cost effectiveness, a model of intervention is presented that takes a patient from acute care management through rehabilitation. Issues discussed include assessment, family training, goal setting, and documentation. A right hemisphere screening tool is included in an appendix for use in acute and transitional care settings where in-depth testing might be inappropriate because of time constraints or the acute or transitory nature of the patient's symptoms.

Evanston Northwestern Healthcare--right hemisphere screen.

This article consists of a screening test that has been developed and used by the speech-language pathologists at Evanston Northwestern Healthcare. It is an informal tool designed to quickly determine the cognitive and communication status of right hemisphere-injured patients and is most appropriate for use in acute care and transitional care settings, where speech-language pathologists are asked to determine whether or not a full evaluation is warranted.

[Is there a correlation between the degree of proliferation of vaginal and urethral epithelium and the incidence of stress incontinence? A contribution to estrogen therapy in stress incontinence]. / Besteht ein Zusammenhang zwischen Proliferationsgrad des Vaginal- und Urethralepithels und der Häufigkeit der Stressinkontinenz? Ein Beitrag zur Ostrogentherapie bei Stressharninkontinenz.

The extent of proliferation of the vaginal and urethral epithelium, as well as urodynamic parameters, were studied in 232 patients in order to determine whether there is a relation between the development of stress incontinence and hormone-related epithelial proliferation. A higher build-up of vaginal than of urethral epithelium was found in 74% of the patients. Even in post-menopause patients, epithelial atrophy in the vagina was only found in 29.3%, while in the urethra it was found in 61.3%. Therefore, the vaginal epithelium cannot with confidence be taken as a basis for conclusions concerning the condition of the urethral epithelium. In the group of 145 patients with urinary stress incontinence no link could be established between the extent of proliferation of the urethral epithelium, the urethral occlusion pressure and the functional length of the urethra: The occurrence of an age-related excessively low urethral occlusion pressure (hypotonic urethra) is independent of the extent of proliferation of the vaginal or urethral epithelium. Sedimentation phenomena are also seen equally frequently in cases with atrophic and eutrophic epithelium. Owing to the high percentage of overweight women among those with stress incontinence, the extent of proliferation of the vaginal and urethral epithelium often corresponds to premenopausal cell pictures even in perimenopausal and postmenopausal women; this is a consequence of increased estrogen production in the peripheral fatty tissue. Therefore, estrogen therapy is unsuccessful in women with pure urinary stress incontinence. However, the efficacy of an equivalent therapy, e.g., with estriol, has been confirmed in cases of active and combined incontinence.